The series was compiled over three months, after the CNN Heroes series asked CNN correspondents and anchors to look back and describe their personal heroes.

Topping the list? Fr. Khalil Jaar, a Catholic priest in Jordan who has sheltered ISIS refugees in his parish of St. Mary’s since 2014.

When ISIS first invaded Iraq, Christians were given three choices – to convert to Islam, pay massive fines, or die. Many of these Christians fled to nearby Jordan, along with thousands of refugees fleeing both the civil war and ISIS in Syria. Since 2011, Jordan, which only has a population of about 6 million, has taken in more than 1 million refugees.

In 2014, churches throughout Jordan started taking in Christian refugees fleeing Iraqi cities like Mosul.

“Father Khalil Jaar never turned anyone away, no matter their faith. Three years on St. Mary’s is still home for displaced Christians…and Father Khalil helps to house hundred of other families outside the church,” CNN reporter Jomana Karadsheh said.

As of October 2014, St. Mary’s parish was housing 100 refugee families, able to offer not much more than sleeping mats and a roof over their heads. At that point, Fr. Jaar had already seen approximately 500 refugees walk through the doors of his parish, seeking shelter.

“Jesus Christ told people, ‘leave everything and follow me,’ ” one refugee, travelling with his 9-month old daughter, told CNN at the time. “So we did.”

“They left their homes in a few hours … leaving everything behind them. It’s a very big shock. That’s why I do my best to help these people to overcome this situation and to (help them) look for a better life,” he said.

At one point, Karadsheh asked Fr. Jaar how he was able to keep going with this mission year after year.

“He says he gets his strength from the refugees who have been through so much and he says he will never ever turn anyone in need away, no matter where they are from or their religion.”

Slowly, Christians are regaining some of their lost ground from ISIS in the battle of Mosul, though the fighting has raged on for months and the death toll continues to rise. Last month, Pope Francis prayed for an end to the violence during a Wednesday general audience.

“My thoughts go out to civilians trapped in the western districts of Mosul and displaced because of the war, to whom I feel united in suffering, through prayer and spiritual closeness,” he said during his March 29 general audience.

“While expressing deep sorrow for the victims of the bloody conflict, I renew to all the call to engage with every effort in the protection of civilians as an imperative and urgent requirement.”